1. Field of the Invention
The invention relates to components for semiconductor material processing equipment. The components are formed of materials that can reduce contamination during semiconductor material processing. The invention also relates to methods of making the components.
2. Description of the Related Art
In the field of semiconductor material processing, vacuum processing chambers are used for etching and chemical vapor deposition (CVD) of materials on substrates. Process gases are flowed into the processing chamber while a radio frequency (RF) field is applied to the process gases to generate a plasma of the process gases. The plasma performs the desired etching or deposition of selected materials on wafers. Examples of parallel plate, transformer coupled plasma (TCP™), which is also called inductively coupled plasma (ICP), and electron-cyclotron resonance (ECR) reactors and components thereof are disclosed in commonly owned U.S. Pat. Nos. 4,340,462; 4,948,458; 5,200,232 and 5,820,723.
During processing of semiconductor substrates, the substrates are typically held in place within the vacuum chamber by substrate holders, as disclosed, for example, in U.S. Pat. Nos. 5,262,029 and 5,838,529. Process gas can be supplied to the chamber by various gas supply systems.
In addition to the plasma chamber equipment, other equipment used in processing semiconductor substrates includes transport mechanisms, liners, lift mechanisms, load locks, door mechanisms, robotic aims, fasteners, and the like.
Plasmas are used to remove materials by etching or for deposition of materials on substrates. The plasma etch conditions create significant ion bombardment of the surfaces of the processing chamber that are exposed to the plasma. This ion bombardment, combined with plasma chemistries and/or etch byproducts, can produce significant erosion, corrosion and corrosion-erosion of the plasma-exposed surfaces of the processing chamber. As a result, the surface materials are removed by physical and/or chemical attack, including erosion, corrosion and/or corrosion-erosion. This attack causes problems including short part-lifetimes, increased consumable costs, particulate contamination, on-wafer transition metal contamination and process drift.
In light of these problems, plasma processing chambers have been designed to include parts, such as, disks, rings, and cylinders, that confine the plasma over the wafer being processed. However, these parts are continuously attacked by the plasma and, consequently, ultimately erode or accumulate polymer buildup. Eventually, these parts suffer such wear that they are no longer usable. Those parts with relatively short lifetimes are commonly referred to as “consumables.” If the consumable part's lifetime is short, then the cost of ownership is high. Erosion of consumables and other parts generates contamination in plasma processing chambers.
Because of the erosive and corrosive nature of the plasma environment in such reactors, and the need to minimize particle and/or metal contamination, it is desirable for components of such equipment, including consumables and other parts, to have suitably high erosion and corrosion resistance. Known parts have been formed of aluminum-based materials. However, the high ion bombardment by the plasma can erode and corrode these materials, producing unsatisfactory levels of contamination (e.g., particulate contamination and metallic impurity contamination).
In view of the high purity requirements for processing semiconductor materials there is a need for components of semiconductor processing apparatus composed of materials that provide improved resistance to physical and chemical attack, including erosion, corrosion and/or erosion-corrosion, to minimize the associated contamination of semiconductor materials during their processing. Materials that can increase the service life of components of the equipment and thus reduce the down time of the apparatus, would contribute to reducing the cost of processing semiconductor materials.